Sham and Apex Resected (AR) Heart at Day 21 (image) Cell Press Share Print E-Mail Caption The AR heart is more rounded and the apex is line by a scar coposed of Collagen (red). Credit Stem Cell Reports, Andersen et al. Usage Restrictions Credit Required Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.